The present disclosure relates to a multilayer ceramic capacitor and a board having the same mounted thereon.
A multilayer ceramic capacitor, one of multilayer chip electronic components, is a chip-shaped condenser mounted on printed circuit boards of various electronic products such as display devices, for example, liquid crystal displays (LCDs), plasma display panels (PDPs) and the like, as well as computers, smartphones, mobile phones, and the like, to charge and discharge electricity therein.
Since such a multilayer ceramic capacitor (MLCC) has advantages such as a small size, high capacitance, ease of mounting, or the like, such a multilayer ceramic capacitor may be used as a component in various electronic devices.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked while being interposed between the dielectric layers.
Since the dielectric layer has piezoelectric and electrostrictive properties, a piezoelectric phenomenon occurs between the internal electrodes when a direct current (DC) or alternating current (AC) voltage is applied to the multilayer ceramic capacitor, such that vibrations may be generated.
These vibrations may be transferred to a board on which the multilayer ceramic capacitor is mounted through external electrodes of the multilayer ceramic capacitor, such that the entirety of the board is a sound radiating surface to generate a vibration sound, noise.
The vibration sound may be within an audio frequency range of 20 to 20,000 Hz, which may cause listener discomfort and is referred to as an acoustic noise.
Recently, a degree of the acoustic noise has become an important factor determining quality of the multilayer ceramic capacitor.
In accordance with an increase in capacitance of the multilayer ceramic capacitor, a mechanical deformation amount of dielectrics may be inevitably increased. Therefore, various methods for solving this problem have been attempted.
Among these methods, a method of controlling an acoustic noise by controlling an amount of solder used to bond the board and the multilayer ceramic capacitor to each other has been disclosed.
However, in this method, bonding strength between the board and the multilayer ceramic capacitor is decreased by an amount in which the solder is decreased, and it is difficult to expect a large decrease in the acoustic noise even in a case in which an amount of the solder is decreased.
As another method, a method of changing an internal structure of the multilayer ceramic capacitor is present.
However, in the method of changing an internal structure of the multilayer ceramic capacitor, generally, a size or a form itself of a product is mainly changed, such that an appropriate method of mounting the multilayer ceramic capacitor needs to be separately introduced.
As another method, a method of controlling a direction in which the multilayer ceramic capacitor is mounted is present.
However, in the method of controlling a direction in which the multilayer ceramic capacitor is mounted, it is necessary to separately align the direction in which the multilayer ceramic capacitor is mounted, such that a separate preprocess may be required.
Meanwhile, in the multilayer ceramic capacitor, external electrodes are formed on the sintered ceramic body and then a process for sintering the external electrodes is performed.
Here, stress may occur during the sintering process, and radiating cracks may occur due to the stress.